Backpack



FIG. 1 is a front, perspective view of a backpack showing our new design in an open configuration;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is a front perspective view thereof in a closed configuration.

The features shown in broken lines are portions of the backpack forming no part of the claimed design. 

CLAIM The ornamental design for a backpack, as shown and described. 